Electrically-wound clock



April 21, 1931. c. E. DE LONG ELECTRICALLY WOUND CLOCK originalFiled'OCt- 4, 1926 Patented Apr. 21, 1931 UNriED vSTATES erica CHARLESE. YDIL LONG, OF SAN DIEGO, CALIFORNIA, ASSIGNOR TO SAN GAMO ELECTRICCOMEANY, OF SPRINGFIELD, ILLINOIS, A CORPORATION OF ILLINOISELECTRICALLY-WOUND CLOCK Original `application. filed October 4, 1926,Serial No.

The present invention relates to electrically wound clocks, and isdivisional of my copending application, Serial No. 139,293, led October4, 1926. More particularly the invention relates to clocks wherein theenergy for winding the main spring is derived from a small electricmotor, generally incorporated in the clock.

Heretofore, in clocks of this type, the customary method of controllingthe motor, i. e., stopping and starting the same with the winding andunwinding of the clock spring, has been to open and close the motorcircuit, through switch mechanism made. responsive tothe tension of themam spring, or actuated by the winding and unwinding of the springthrough a predetermined number of turns. Electrical contact requiringfrequent opening and closing are always subject to pitting, arcing,etc., and hence these prior clocks have not been commerT ciallysuccessful, owing to the imperative necessity of a clock givingreliability of operation over indefinite periods of time, withoutservice or attent-ion.

The fundamental obj ect of the present invention is to obviate thedifficulties inherent in the use of electrical contacts by providing anelectrically wound clock in which the control exercised 'over the motoris in the nature of a mechanical braking thereof rather than an openingand closing of the motor circuit. Small motors of the induction type arenow obtainable, which will permit of braking down to a dead stallwithout injury to the motor and without any objectionable loadiuctuation being imposed on the line supplying the motor. Such motorscan ber slowed down, stopped and started in definitely through brakingretardation without deterioration of any of the working parts of theclock mechanism or motor.

A further object of the invention is to provide improved brakingmechanism which will be sensitive in its-action, to the end of keepingthe winding and unwinding limits of the clock spring within acomparatively small range, whereby an approximately uniform tension isalways maintained on the clock spring. The braking control forming139,293. Divided and this application filed June 2,

serial No. 195,880.

the essence of this invention enables this tensional variation of theclock spring to be maintained between much closer limits than ispracticable in a clock wherein the motor circuit is opened and closed bycontact mechanism. Because of the pitting and deterioration of thecontacts in these latter types of electrically wound clocks it is notpracticable to open and close the motor circuit with the frequencyrequired to obtain this close regulation of the clock spring tension.Such close regulation of the clock spring tension, as'obtained by thepresent braking control, augments the time keeping accuracy of theclock.

Referring to the accompanying drawing illustrating a preferredembodiment of my invention:

Fig. 1 is front or face view of a clcck movement embodying theinvention, the front mounting plate being broken away to illustrate partof the gear train;

Fig. 2 is a transverse sectional view taken on the plane of the line 2-2of Figure 1, the major part of the `gear train being` omitted from thisfigure for clarity of iilustration; A 1

Fig. 3 is an axial sectional View of the threaded countershaft andcooperating threaded gear, and i l Fig. 41 is a fragmentary detail viewof the two cooperating braking elements.

The clock movement may be of any preferred design or construction, thepresent invention being capable of embodiment in practically any type ofmovement with very little modification of standard construction. Asexemplary of a typical construction of clock, I have shown in Figs. 1land. 2 a design wherein the gear train, main spring, etc., are allmounted in a frame structure comprising front and rear disc-like platesv8 and 9, held in spaced relation by posts 11.

and the hour hand isV is preferably mounted on the outer side of therear plate 9, the frame of the motor having extending lugs 17 which aresecured to spacing posts 18 by screws 19. This motor is referably of asmall induction type, capa le of being connected directly to an ordinarylighting circuit. The armature shaft 21 of the motor extends through theback plate 9 and carries a small pinion 22 which meshes with arelatively large gear 23 on an arbor 24 pivoted between the end plates.The pinion 22 and gear 23 are pref* erably located in close proximity tothe back wall 9, the large gear 23 constituting the rotating element towhich the braking retardation is applied, as will hereinafter a r.

he reduced speed of the arbor 24 is transmitted through a pinion 25,mounted n this arbor, to a large gear 26 .mounted on a second arbor 27,also journaled in the end lates 8 and 9. A pinion 28 mounted 0n t issecond arbor transmits the reduced speed thereof to a large gear 29mounted on a third arbor 31, also journaled at its endsI in the frontand rear plates. On this `third arbor is a pinion 32 which meshes with alarge gear 33 which is pinned to the main spring arbor 34. The secondandthird arbors 27 and 31, together with their respective gears, have beenomitted from Fig. 2 to avoid obscuring the illustration of the brakingmechanism. As shown in this ligure, the main spring 35 and spring barrel36 are mounted on the main spring arbor 34, preferably adjacent the backplate 9, the spring barrel being freely rotatable on the arbor. Theinner convolution of the lnain spring 35 is suitably secured to thearbor 34, as by the pin 37. The outermost convolution of the main springis suitably connected to the spring barrel, whereby the tension of thesprin operates to rotate the spring barrel, and t e ring ear 39extending from the periphery thereo This ring gear 39 meshes with ainion 41 mounted on the central, minute land arbor 12. Any suitableescapement mechanism 42 is operatively connected to the minute handarbor 12 through a suitable gear train, not shown.

Extending substantially parallel to the main s ring arbor 34 is acountershaft 44 which as its ends suitably journaled in the front andrear lates 8 and 9. Formed on this countersha t is an enlarged threadedportion 45 over which screws an internally threaded gear 46 which has arelatively wide toothed periphery for meshing with the gear 33 of themain spring arbor 34. A second gear 47, which is rigidly pinned or keyedto the countershaft 44, meshes with the ring gear 39 of the main springbarrel. Extending from one side of the relatively wide gear 46 is agrooved collar 48 which is embraced by the forked end 49 of a brakinglever 49. Such lever extends transversely through the various parts ofthe gear train above described (Fig. 1) for pivotal iliounting at on apost 51 extending forwardly from the back Wall 9 at a point adjacent tothe gear 23 and arbor 24. The pivotal mounting of the lever 49 on thepost 51 is preferably effected b i forking this end of the lever toembrace t e post and to receive the pivot pin 50 passing through thelever and post. Adjacent to its pivoted end, the lever carries anadjustable screw member 53 having a. threaded portion 54 screwingthrough a tapped hole in the lever. The inner end of this screw isadapted to bear against a braking surface 55 rotating with the gear 23.This braking surface 55 may be the actual side of the gear, butpreferably it consists of a disk of fibre or some similar materialsecured to the gear.

In the operation of the clock, the energiz tion of the motor will drivethrough the gear train previously described, which will operate toimpart a slow speed winding rotation to the main spring arbor 34. As thedriving gear 33 of this arbor is revolving, it is also revolving therelatively wide countershaft gear 46, with which it is in continuousmesh. With tension existing in the spring the spring barrel 36 will, ofcourse, a so be rotating in the same direction as the arbor 34, but therotation of this spring barrel will be so slow compared to the windingrotation of the arbor that it may be considered as practicallystationary. Hence the gear 47 and threaded portion 45 of thecountershaft 44 will remain almost stationary, with the result that theappreciably higher speed of rotation of the gear 46 on the countershaftwill cause this gear to screw inwardly towards the back plate, thethread having this direction of lead. As the spring approaches thedesired limit of its winding tension the grooved collar 48 willgradually swing the braking lever 49 backwardly. This will bring the endof the screw member 53 against the braking face 55 on the gear 23,exerting a gradual braking retardation thereon, until the motor 15ceases, or substantially ceases rotation, at the point where the desiredwinding tension has been given the spring 35.

With the main spring arbor 34 inert, or substantially inert, as theresult of the aforesaid braking action, the continued rotation of thespring barrel 36, and hence of the countershaft 44 will gradually screwthe wide gear 46, which is now held against rotation, backwardly alongthe thread 45 towards the front plate 8. When the spring barrel hasrevolved through a given angular distance, corresponding to the lowerpredetermined limit of its spring tension, the gear 46 will have movedbackwardly along the countershaft 44 to the point where the brakingfriction of the screw member 53 will be removed from the brake surface55. Thereupon the motor 15 will be permitted to resume rotation, withthe result that the main spring will again be wound to a predeterminedtension through a repetition of the cycle previously described.

In the event of the supply of current to the motor being interrupted,the reserve tension of the main spring 35 will be sufficient to continuethe operation of the clock for a considerable period of time. As soon ascurrent again comes back on the line the motor will rewind the mainspring to its previous working tension. By adjusting the screw 53 in itsthreaded mounting in the lever 48, the upper limit of the working springtension can be shifted to any desired; point in the total rangeof springtension.

What I claim as my invention and desire to secure by Letters Patent, is-

1. In a device of the class described comprising a spring, a springbarrel and an electric motor for winding said spring, the combination oftwo cooperating threaded members disposed eccentrically of said springbarrel and cooperatively connected to the opposite ends of said spring,and brake mechanism responsive to predetermined relative movementbetween said threaded members for applying a gradual braking retardationto said electric motor.

2. In mechanism for winding a spring motor comprising the spring, anarbor and an electric motor for winding said spring, the combination ofa countershaft disposed eccentrically of said arbor, two cooperatingthreaded members on said countershaft, means rotatably connecting saidthreaded members with the opposite ends of said spring, brake mechanismresponsive to predetermined relative movement between said threadedmembers for applying a gradual braking retardation to said electricmotor, and means for adjusting said brake mechanism.

3. In mechanism for winding a spring motor comprising the spring, and anelectric motor for winding said spring, the combination of a pair ofcooperating screw threaded members having geared connection with theopposite ends of said spring to be revolved thereby, and lever actuatedbrake means responsive to predetermined relative movement between saidmembers for applying a gradual braking retardation to said motor. 4. Inmechanism for winding a spring motor comprising the spring, an arbortherefor, a spring barrel, and an electric motor for Winding saidspring, the combination of a pair of interacting relatively movablemembers,` gear means for driving Vone of saidI members from said arbor,gear means for driving the other of said members from said springbarrel, a'lever having stationary pivotal mounting adapted to be swimgby relative movement between said members, and brake mechanismresponsive to said lever for applying a gradual braking retardation tosaid electric motor.

5. In mechanism for winding a spring motor comprising the spring, anarbortherefor, a spring barrel, an electric motor and a gear trainoperatively connecting said electric motor with said spring, thecombination of a rotating brake surface associated with said gear trainadjacent to the motor end thereof, a gear rotating with said arbor, agear rotating with said spring barrel, a countershaft driven by one ofsaid gears, a thread on said countershaft, a gear screwing over saidthread and driven by the other of'said gears, a lever responsive torelative axial movementk between said countershaft and said gear mountedthereon, and a screw member having adjustable threaded mounting in saidlever for applying gradual braking pressure to said brake surface.

6. In mechanism for winding a spring motor comprising the spring, anarbor therefor, a spring barrel, an electric motor and a gear trainoperatively connecting said electric motor with said spring, thecombination of a rotating brake surface adjacent to the motor end ofsaid gear train, a countershaft comprising a threaded portion, means fordriving said countershaft from said barrel, an internally threaded gearscrewing over the threaded portion of said countershaft, means fordriving said latter gear from said arbor, a collar on said latter gear,a lever' having a forked end embracing said collar and arranged to beswung by the axial movement of said threaded gear along saidcountershaft, and a pin having adjustable threaded mounting in saidlever and actuated thereby for engaging with said brake surface.

7. In mechanism for winding a spring motor, the combination of thespring, an arbor therefor, a spring barrel, an electric motor, a pinionon the armature shaft of said motor, a spur gear driven by said pinion,a rotating brake surface mounted on one side of said spur gear, a geartrain driven through said spur gear and operatively connected with saidspring, a gear rotating with said arbor, a gear rotating with saidspring barrel, a countershaft driven by one of said latter gears, athread on said countershaft, a gear screwing over said thread and drivenby the other of said latter gears, a lever responsive to relative axialmovement between said countershaft and said gear mounted thereon, andmeans actuated by said lever for applying gradual braking pressure tosaid rotating brake surface, to stop said electric motor by stalling thesame.

8. In mechanism for Winding a spring motor, the combination of thespring, an arbor therefor, a spring barrel, an electric motor, a pinionmounted on the armature shaft of said motor, a spur gear meshing withand driven by said pinion, a. rotating brake surface disposed coaxiallywith said spur gear and rotating therewith7 a gear train operativelyconnecting said electric motor with said spring, a pair of interacti ingrelatively movable members, gear means for driving one of said membersfrom said arbor, gear means for driving the other of said members fromsaid spring barrel, a lever having stationary pivotal mountingr adaptedto be swung by relative movement between said members, and brake meansresponsive to said lever for applying gradual braking pressure to saidrotating brake surface, to stop said electric motor by stalling lm thesame.

CHARLES E. DE LONG.

